A tutorial for searching with blekko

Welcome! This tutorial is intended to teach you some of the unique features of the blekko search engine. It starts with search basics, explains blekko’s special slashtag feature, and finishes up by discussing privacy and safe searching.

For more general help, please see our help pages.

Search basics

Asking blekko to search for several words means that we will interpret these two words liberally. We’ll include results with both singular and plural forms of words, for example we will match “word” as well as “words”. We might return results containing “multiple” instead of “several,” because these words are similar. And we will include results where “several” and “words” aren’t next to one another. This is the way all search engines do normal searches.

Results for [several words]

If you add quotes around individual words: “several” “words”, we will return results containing only these exact words, without synonyms or plurals. If you add quotes around a phrase: “several words”, we will require the words to be next to each other, in that order, in the results.

Results for "several words"

You can ask for results that do not include a particular word by adding a minus sign before it: pie recipes -apple. This is useful if you’ve done a search and it returned many unwanted results containing the same word, in this example “apple”. You can negate several words: apple recipes -pie -crisp.


Slashtags are blekko’s way of giving you access to the full power of our search engine, without making you wade through lots of graphical UI or menus. In fact, the main feature of slashtags is that they let blekko ship features that our graphics designers could never think up a pretty interface for. Think of them as the command line of search engines.

Slashtags are expressed by typing additional words into the search box. As an example, searching for blekko /blogs will return only results that are blogs, and blekko /blogs /date will sort that result by date. The most interesting uses of slashtags can produce results that are impossible to generate in other search engines.

Slashtags are divided into 4 main types.

/ps=N is an example of a utility slashtag; it modifies the number of results blekko will display.

Topical slashtags are built by human editors, and power blekko’s human curation and anti-spam features. For example, the /health slashtag contains around 200 websites with high-quality health information.

cure for headaches /health

To see the full list of websites in /health, type /view /health into the search box.

The websites in /health are selected by blekko’s in-house librarian team, working with volunteer medical professional editors. Our policy for this slashtag is that it is limited to websites with conventional medicine content where 100% of the content is doctor-reviewed. If you’re interested in non-conventional medicine, we also have

And that’s just the alternatives beginning with the letter “a”! This focus on source authority and categorized search is basically impossible to replicate with an algorithm, or by typing words into the search box.

Topical slashtags can also be combined with /date, to change the sort order. For example:

debate /libertarian /date

A complete list of high-quality blekko-built topical slashtags can be found by clicking on the “slashtag directory” link on any results page. A few important ones include: /topnews, /sports, /politics, /gossip, /arts, /business, /culture, and /fashion. If you’re wondering why we chose some of these categories (like /fashion and /home), the reason is that in order to reduce spam for searchers who don’t explicitly use slashtags, we needed to create slashtags for every category on the Internet that has a lot of advertising money behind it. Advertising money causes webspam to spring into existence, and our anti-spam goal requires us to be able to clean up searches in all of the major spammed-up categories.

As an example of how these slashtags can be useful, look at the difference between the search results for:

Another example of using topical slashtags to slice-and-dice the web into different viewpoints are searches about the controversial topic of climate change. Compare:

Topical slashtags can be included within each other. In addition to the 200 general health websites in the /health slashtag, /health also includes a bunch of specialist slashtags named /cardiology, /diabetes, and so on. These specialist slashtags can be used directly, and are also included in /health. (You can view the list of included slashtags in /health by looking at the top of /view /health.)

Algorithmic slashtags are generated by algorithms built into blekko’s crawler. For example, websites and parts of websites that are blogs are identified in our crawler. Additional examples of algorithmic slashtags include /forums and /people. /people is used to search pages that are resumes, biographies, and personal homepages. /forums limits your search to forum websites.

Shortcut slashtags are used to access 3rd party services. Examples include:

These searches are farmed out to bing image search, bing maps, YouTube, Yahoo Finance, Weather Underground, Wolfram Alpha, and so forth.

If you use multiple slashtags together in a single search, the results will have to be in all of the slashtags. For example obama /topnews /conservative will only include results from websites which are included in both the /topnews and /conservative slashtags. Some combinations, however, do not work: 3rd party services slashtags such as /images and /videos cannot be combined with topical slashtags like /politics.

You can create your own topical slashtags. This is discussed in the 2nd half of this tutorial.

Boosted and auto-boosted slashtags

Topical slashtags can be used in 2 different ways: exclusively within a slashtag headache /health or as a boost headache +/health. In the exclusive form, all results will be from the curated sites in the /health slashtag. In the boosted form, the entire web will be searched, but any results in the /health slashtag will have their rank boosted. Boosting allows highly-ranked results that are not in the slashtag to still be included in the final results. A search with exclusive /health will never contain spam if /health is kept spam-free; the boosted +/health is unlikely to contain spam, but it’s always possible that queries like autism cure +/health will contain a highly ranked result from outside of /health which may be considered spam or off-topic by a human curator.

A mainly non-health keyword combined with boosted +/health (such as obama +/health) will frequently include results from outside the /health slashtag. (Compare to obama /health.)

In order to fight spam for users uninterested in explicitly using slashtags, we attempt to guess the topic of every slashtag-less search, and boost a slashtag for it. This is called auto-boosting, and it currently happens about 1/3 of the time for non-navigational searches. For example, searching for cure for headaches will auto-boost +/health. If you find the auto-boosted slashtag to be unhelpful, you can turn off auto-boost by adding /web to your search: cure for headaches /web.

Negating slashtags

Topical and algorithmic slashtags can be negated by using the minus sign: blekko -/blog will return non-blog webpages mentioning blekko, while blekko -/tech will return results from websites which are not in the /tech slashtag. Negating slashtags work better with broad slashtags (such as /blog) than with narrow ones (like /gossip).

Every logged-in user has a personal /spam slashtag which is negated in every search that they do. Adding a website to this slashtag means it will disappear from your personal results.

Other examples of interesting uses of negating slashtags include searching less-popular news websites, e.g. romney /news -/topnews, or looking at popular but not liberal news websites: romney -/liberal /topnews.

We’ve even created slashtags intended to always be used in a negative fashion — there are a series of slashtags containing the most popular 10, 100, 1,000, 10,000, and 100,000 websites on the Internet. It can be very interesting to exclude these websites from searches, in order to deliberately avoid popular websites. These slashtags have names like /top10/top10, /top10/top1000, /top10/top10k, and /top10/top100k. (Why are these slashtag names more complicated than usual? It’s because they are owned by the user named “top10″. This is fully explained in the 2nd half of this tutorial.) An example search using these slashtags is searching for news about Obama that’s not in the most popular 100,000 websites: obama /news -/top10/top100k.

A few search tips

If you’ve arrived at a result webpage and can’t see one of your search terms, try using control-f (PC, Linux) or command-f (Mac) to search within the webpage. If you still can’t find the search term, remember that it might be present only in the anchortext of an incoming link.

Search engines usually ignore capitalization and punctuation. There are a few terms, like C++ and C#, for which punctuation can be searched for, but in most cases punctuation is completely ignored. For example, if you’re searching for a phone number, (650) 555-1212 is the same as 650 555 1212. Punctuation in quoted phrases is also ignored, but the order of the words is preserved. “650 555 1212″ will successfully match variations of the phone number written with parentheses and dashes.

The order of words in your query is somewhat ignored. If you wish to enforce word order, use quotes: compare rare phrase to “rare phrase”. Since blekko indexes pairs and triples of adjacent words, you should put words together that belong together. If you’re interested in webpages mentioning John Smith and Fred Brown, searching for John Smith Fred Brown will return much better results than searching for John Fred Smith Brown.

Search engines mainly work on words, not sentences. Compare:

Safe Searching

blekko’s safe-search features are similar to the safe-search offered by other search engines. By default, safe search is set to “moderate”, which means that porny results will be visible only if a majority of results are porn. If you wish to always see all results, click on “prefs” in the upper right and set safe-search to “disabled”. Alternately, you can set safe-search to “strict”, and porny results will never be shown. Keep in mind that our porn classifier is not 100% accurate, and naughty search terms can return occasional porny results even when safe-search is set to strict. Also, remember that if autoboosted slashtags are getting in the way of the results you want, add /web to disable autoboosting.

The blekko user preferences menu


blekko is committed to search privacy, and uses “privacy by design” to retain minimal information. We discard almost all personal information, such as your IP address, after 48 hours. Please see our privacy policy for full details.

To increase your privacy, we recommend that you click on the “prefs” menu in the upper right, and select “Always use HTTPS on blekko”, which keeps your searches more private against the bad guy listening to the insecure WiFi in the coffee shop, and your Internet Service Provider (ISP). Many ISPs collect data on your browsing habits, and sell this data to marketing companies.

Our “HTTPS Preferred” feature defaults on, and means that we will send you to the HTTPS (encrypted) version of a result page, if we know that one exists.

We already do not track you in the way the DoNotTrack initiative recommends, but if you have DoNotTrack enabled in your browser, or select “Less Logging”, we will not include your searches in our fully anonymized search summaries, even in the data that we use to study and improve results of our search engine.

You can turn off ads if you like; we can’t guarantee that our ad providers are respecting your privacy. Finally, selecting “Super Privacy” will keep you as private as possible, although you should note that the “No External DYM” option will degrade your search results, sometimes significantly.


Aside from the use of private slashtags and the /spam slashtag, blekko currently does no personalization of results. If we do so in the future, we will provide a way to know personalization is happening, and to disable the feature. We do sometimes localize results; if so, it will be obvious, and adding /web will disable localization.

Making blekko the default or optional search engine in your web browser

You can make blekko your default search engine in most browsers, including Firefox, Chrome, Safari, and Internet Explorer.

For more information

Please see Advanced Search Features for further information about searching with blekko. If you have questions or wish to offer feedback about how good or bad our results are, please use the “file bugs/feedback” link on any search result, or send email to support@blekko.com. Thank you for your interest in blekko, and thank you for reading this tutorial!

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Advanced Search Features

Be sure to review the tutorial for searching with blekko before you read this page.

Creating your own slashtags

Logged-in users can create their own topical slashtags by clicking “create a slashtag” on any results page. At creation time, you can choose if the slashtag will be public or private. Your public slashtags can be used by other users with the name /yourusername/yourtagname, for example /greg/mc is a slashtag that I (user “greg”) created to search the websites of the members of the San Francisco-based Media Consortium. A shortcut to view or edit this slashtag is to type /view /greg/mc into the search box. You can invite other users to help edit your slashtags. Topical slashtags can be included within each other; you can include blekko slashtags in your personal slashtags if you wish to extend a blekko slashtag with additional websites.

The topical slashtags such as /sports that we’ve been talking about previously in this tutorial series are actually slashtags created by the user named blekko. The full name of /sports is /blekko/sports. Whenever you use the shortcut /sports, we will first look for /yourusername/sports, and if it does not exist, /blekko/sports.

The individual elements in a slashtag can be narrower than an entire website. The possibilities are:

  • an entire website: quora.com
  • a prefixed subset of a website: espn.go.com/nfl
  • an individual URL: foo.com/bar.html
  • a wildcarded subset of a website: stackoverflow.com/*javascript

Subsets of a website are useful on websites with a hierarchy of content; espn.go.com has separate prefixes for football (/nfl), baseball (/mlb), and basketball (/nba). Wildcards are useful for websites where the URL contains the topic of the webpage, and the topic tends to contain whatever you’re looking for. These four possibilities can’t be successfully used with every topic and website, but they work for most.

Individual slashtags are limited to 25,000 entries; the maximum count for included slashtags is 125,000.

Sort order, and date ranges

In addition to the usual relevance-sorted results, blekko allows you to sort by date by adding /date. Date sorted results only include webpages which appear to be explicitly dated, such as newspaper articles, blog postings, press releases, etc. Sorting by date may hurt relevance. For example, webspam can easily appear in obama /date, because “obama” is a fairly common word in spam blogs (splogs). Using a topical slashtag can help improve relevance: try obama /topnews /date or obama /politics /date to avoid spam and improve quality. Another way to fiddle with relevance is to replace /date with /fastdate or /date /more, or adding quotes around phrases. /fastdate will increase relevance by searching only webpage titles, and only returns very recent results; it is useful when you have too many low-quality results in a date-sorted query. /date /more returns more results if there are lots of results, and is useful when you wish to see every mention of a search term. Plain /date will behave like either /fastdate or /date /more, depending on how recently popular the search terms are.


/fastdate and /date /more are more interesting in searches that always have a lot of recent content: try

If you’d like dates limited to a date range, but still want a relevance sort, use /daterange like this:

Date ranges can also be relative, such as

Using “last week” is especially useful if you’d like to monitor search terms using an RSS feed.

RSS feeds and email alerts

Adding /rss to any search will result in output in rss, which can be read with your favorite rss reader, such as NewsBlur.com or Google Reader. RSS feeds can also be turned into emails by services such as https://www.feedmyinbox.com/. An RSS feed turned into email is roughly equivalent to a Google Alert.

/rss applied to a non-date search is fairly boring; new items will appear only if something new appears in the top 20 results for the search. Adding /date makes sure that new dated material appears, but might bring in too much webspam. Using /daterange=”last week” instead of /date helps exclude spam from dated material. Note that material without a date will never be returned by /date or /daterange. If you would like to see everything new about a topic, we recommend a combination of 2 rss feeds: one non-date with /ps=100, and one with /date or /daterange.

The number of results examined in rss feeds can be increased by adding /ps=100 to the search. You will find that the optimal number of results depends upon the amount of spam present in the search.


Not getting what you want? Try adding quotes around words to make them exact, or add /web to turn off auto-boost. Try adding /noblend, which will reduce the number of results, but may make exclusions and quoted words/phrases much more exact.

You can always contact us at support@blekko.com for help. Contacting us not only gets you an answer for your question, but it also helps us improve blekko’s behavior and our documentation.

Advanced Search Tips

blekko does not currently support Boolean searches, which use AND, OR, NOT, and parentheses. AND is implicit in all searches, and NOT is expressed using a minus sign: tiger woods -affair. There is no way to express an OR with blekko; use multiple searches instead. We also don’t support using * as a wildcard in the search box.

The number of results claimed for a query are just an estimate and shouldn’t be taken too seriously. This is true of all search engines; for an overview, please see the blog posting Why Google Can’t Count Results Properly by Danny Sullivan of Search Engine Land.

Due to the way search queries are evaluated, it’s impossible to get more than 1,000 results for a query out of the search engine, even if there are supposedly millions of results. Often only 500-600 results is the maximum.

The next section, Webgrep, hows how you can get an accurate results for searches over our entire database.


Search engines are fast because we’ve built inverted indices for all the words we have found in webpages. We then look things up in these indices in ways that prevent us from returning all of the results, especially if there are a large number of results.

It’s possible for us to instead search by looking at every webpage in our crawl individually. This takes about 10 hours for our current crawl, which is 1 petabyte of data (1 million billion characters) in 4 billion webpages. This kind of computing is called MapReduce. There could be 10s to 100s of millions of results for this kind of query, and we can return them all.

We can also do special searches this way, such as searches involving punctuation, and searches within the HTML text of webpages. This last kind of search is handy for asking questions like: What RDF microformats are in common use? What jQuery libraries are popular?

For more details, see https://blekko.com/webgrep.


If you would like to make programmatic access to blekko search results, we do offer an API. Results can be fetched either as XML or JSON. Please contact apiauth@blekko.com for more details. The API can also be used to manipulate slashtags from a program.

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How do I remove blekko from my Safari browser?

Try the following to remove the program that is causing this:

1. From the Applications folder, open “Uninstall Genieo” and follow the instructions.
2. Close and re-open your browser. The search box should search the correct search engine now.

To change your homepage, go to Safari -> Preferences, General Tab, Homepage section and enter the URL of the homepage you would like to use.

If this doesn’t work, please contact us at support@blekko.com.

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Is there a slashtag directory or list?

blekko has hundreds of slashtags that are being curated by experts across the web. You can see the full list of topical slashtags here.

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About blekko’s Search Results

At blekko, we believe that the index is the core of any search product.  It is the only place where a search engine can provide editorial differentiation.  Consequently, we have 1,500 servers that crawl the web continuously to make sure blekko has an up-to-date, relevant index from which to serve results.

It is our goal to serve results for all queries from our own index. Our current index size sits at around 4 billion pages. While it grows every day, the web is much larger than this. As a result, sometimes we turn to third parties to help us return the best results. You can access some of these third party results directly by using specific slashtags, such as /twitter, /facebook, and /bing. But just like we do with our own slashtags, we sometimes blend them in to enhance the search experience.

Third Party APIs that we use include the usual suspects that you would expect to see: Amazon, Bing, Facebook, Flickr, and Twitter; as well as more specialized sites such as Carfax, FedEx, Indeed, Rotten Tomatoes, Truveo, and USPS.

We will continue to seek out the best ways to improve the search experience on blekko. But rest assured that the heart of blekko will always be its own index.

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How do I remove blekko as my homepage and default search engine in Internet Explorer (IE)?

By default, downloading the blekko spam-free search bar also changes your homepage and default search engine to blekko. When downloading the search bar, you should have a chance to choose what settings on your IE (Internet Explorer) browser to change. Please let us know if you encounter any problems with choosing these settings while installing.

(For help on uninstalling the search bar, please click here.)

Here are instructions for changing some of those settings manually.

To change your homepage:

For IE9: http://windows.microsoft.com/en-US/windows7/Change-your-Internet-Explorer-9-home-page

For earlier versions of IE: First, go to the URL of the page you want to be your home page. Here are some common homepages: Google, Comcast, MSN, Yahoo!, AOL. If you would like one of those to be your homepage, click on the link. While you are on the page that you’d like to be your homepage, follow these instructions.

1. Click on the down arrow next to Tools in the upper right hand corner of your browser.
2. Click on “Internet Options”. This will bring up a pop-up.
3. Click on the “General” Tab.
4. The very top section says “Home page” and is for changing your homepage.
5. Delete http://blekko.com from that area.
6. Click on “Use current” to set the URL you are on as your homepage.
7. Click on “OK” on the bottom of the pop-up. This should close the pop-up.
8. Close your browser.
9. Re-open your browser.

To change your default search engine:

For IE9: http://windows.microsoft.com/en-US/windows7/Search-with-the-Internet-Explorer-9-Address-bar

For earlier versions of IE:
1. Click on the down arrow next to the magnifying glass icon in the default search box in the upper right hand corner of your browser.
2. Click on “Find More Providers”
3. You’ll be in a page called the “Internet Explorer Gallery” that lists search engines you can choose to add to your IE. Scroll down and click on “Google Search”.
4. Click on the button that says “Add to Internet Explorer”
5. This will bring up a pop-up asking if you want to add “Google” as a search provider. Check the box that says “Make this my default search provider” and click on “Add”.
6. Google should now be showing as your default search provider in the search box.


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How do I remove blekko as my homepage and default search engine in Chrome?

By default, downloading the blekko spam-free search bar also changes your default search engine to blekko. When downloading the search bar, you should have a chance to choose what settings on your Chrome browser to change. Please let us know if you encounter any problems with choosing these settings while installing.

(For help on uninstalling the search bar, please click here.)

Here are instructions for changing these settings manually.

To change your startup page (homepage):

1. Click on the wrench icon to the right of the address bar. This should be the wrench for Chrome and not for any toolbar. (Some versions of Chrome will have three horizontal bars instead of a wrench. Click on that if you see that instead of the wrench.)

2. A pop-up will appear. Scroll down and click on “Options” or “Settings.”

3. Click on the “Settings” tab on the left hand side.

4. The section marked “On startup” determines what page is shown when you open your browser. Make sure the radio button is checked for “Open a specific page or set of pages:” and click on “set pages.” (if you want New Tab page or to open your last session instead, click one of those radio buttons and skip to step 6)

5. Click on the X mark to the right of http://blekko.com to delete that. Then enter the URL of the homepage you’d like to use in the “Add a new page” section. Some common homepages are Google: http://www.google.com, Comcast: http://xfinity.comcast.net/, MSN: http://www.msn.com/, Yahoo!: http://www.yahoo.com/, AOL: http://www.aol.com. Hit “OK” to close the pop-up.

6. Close your browser.

7. Re-open your browser.

To change your default search engine:

1. Click on the wrench in the right hand side. This should be the wrench for Chrome and not any toolbar.
2. Click on “Options” or “Settings.” Make sure you are in the “Settings” tab.
3. In the Search part of the page, choose the search engine from the drop down that you would like to use.
4. Searching in the address bar should use the search engine you chose now.

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How do I uninstall the blekko Spam-Free Search Bar?

Follow these instructions to uninstall the blekko Spam-Free Search Bar:

1. Look on the right hand side of the toolbar for a wrench icon. Click on that.

2. This brings up a menu. Click on “Help”.

3. In the next menu, click on “Uninstall”.

4. This will bring up the Uninstall Wizard. Follow the steps to uninstall the toolbar.

5. Once the program is uninstalled, the toolbar will be gone, but you will still see blekko when you open your browser because some of your browser settings (such as homepage and default search engine) will have changed as well. Here are instructions for changing those settings back in IE (Internet Explorer), Firefox, and Chrome.

6. Re-open your browser. You might need to reboot your computer as well.

If there is no wrench icon, then the toolbar program might not have installed. Instead, the settings on your browser might have changed.
Here are instructions for changing those settings back in IE (Internet Explorer), Firefox, and Chrome.

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What is blekko?

blekko is a search engine that slashes out web-spam, content farms, and malware. We do this by having a smaller crawl of 3 billion pages that focuses on quality websites. We also have a tool called a slashtag that organizes websites around specific topics, and improves search results for those topics.

At blekko we believe in transparency. We created the web search bill of rights to explain our outlook.

Web search bill of rights:

  1. Search shall be open
  2. Search results shall involve people
  3. Ranking data shall not be kept secret
  4. Web data shall be readily available
  5. There is no one-size-fits-all for search
  6. Advanced search shall be accessible
  7. Search engine tools shall be open to all
  8. Search & community go hand-in-hand
  9. Spam does not belong in search results
  10. Privacy of searchers shall not be violated

For more information about searching with blekko, please see our tutorial.

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What is a slashtag?

A slashtag is an easy-to-create custom search engine. It is a tool used to filter search results and helps you to search only high quality sites, without spam or content farms. Slashtags contain a list of websites and when you search with a slashtag, you only search those sites. Some slashtags perform functions such as ordering the results by date.

For example, when you search on diabetes /health, you are searching a set of trusted sites such as nih.gov, cdc.gov, webmd.com, and more. Content farms and spam sites are banished entirely.

blekko has created hundreds of slashtags that are being curated by experts across the web. You can search with these slashtags or create your own.

For more information about slashtags, check out our tutorial.

Posted in getting started, slashtags | 2 Comments